Regarding the integrated energy system centered on a dual-source efficiency heat pump coupled with biomass-air energy, this paper proposes a design method for the evaluation system of the integrated energy system under the consideration of multiple indicators with different weighting rates, in order to solve the problems such as the difficulty of the capacity configuration, the evaluation complexity of later stage, and the difficulty of quantification. By combining the engineering practice, different capacity allocation schemes of renewable energies are given, and based on this, the simulation examples of eight sets of capacity allocation schemes under the dynamic change of the weighting rates of five indicators are established with full consideration of multiple indicators, such as renewable energy consumption rate, carbon emission, investment and operation economy, distribution grid capacity, COP and so on. The results show that the algorithm can calculate the comprehensive performance of different capacity allocation schemes under the changing weights of indicators, and the evaluation system helps to determine the best renewable energy capacity allocation scheme according to the engineering practice.
This paper revolves around the application of the dual stator-winding induction generator in the field of wind power generation. It involves establishing a mathematical model of the dual stator-winding wind turbine and proposing an excitation start-up method for the generator. The study begins by describing the structure, working principle, and excitation start-up method of the dual stator-winding generator, and leverages the Matlab/Simulink to establish the simulation model of the dual stator-winding induction generator. In this study, we conducted simulation and analysis to evaluate the performance and excitation starting method for the generator and carried out a prototype test. The results demonstrate that the dual stator-winding wind turbine can obtain a stable low-voltage power supply at the auxiliary winding end of the generator at different speeds by adjusting the rotor excitation currents, and can provide stable excitation voltage for the rotor end through the converter. Moreover, the stator end of the generator can yield stable-frequency and high-voltage output.
Given $k\ge 2$ and two $k$-graphs ($k$-uniform hypergraphs) $F$ and $H$, an $F$-factor in $H$ is a set of vertex-disjoint copies of $F$ that together covers the vertex set of $H$. Lenz and Mubayi [J. Combin. Theory Ser. B, 2016] studied the $F$-factor problem in quasi-random $k$-graphs with minimum degree $\Omega(n^{k-1})$. They posed the problem of characterizing the $k$-graphs $F$ such that every sufficiently large quasi-random $k$-graph with constant edge density and minimum degree $\Omega(n^{k-1})$ contains an $F$-factor, and in particular, they showed that all linear $k$-graphs satisfy this property. In this paper we prove a general theorem on $F$-factors which reduces the $F$-factor problem of Lenz and Mubayi to a natural sub-problem, that is, the $F$-cover problem. By using this result, we answer the question of Lenz and Mubayi for those $F$ which are $k$-partite $k$-graphs, and for all 3-graphs $F$, separately. Our characterization result on 3-graphs is motivated by the recent work of Reiher, R\"odl and Schacht [J. Lond. Math. Soc., 2018] that classifies the 3-graphs with vanishing Tur\'an density in quasi-random $k$-graphs.
Aiming at the massive operation and monitoring data of distributed photovoltaic equipment, this paper builds a real-time database and a relational database platform. Based on big data mining technology, the distributed photovoltaic power generation equipment status data and the related data are preprocessed and cleaned. Then the failure mode of distributed photovoltaic power generation equipment is counted and analyzed with the data mining algorithm, and the failure severity, probability level, severity level and failure rate of each faulty subsystem is calculated to find out the failure rule and corresponding treatment measures. At the same time, a new energy remote expert fault diagnosis software system has been developed to realize early warning, fault cause analysis and fault trend analysis of distributed photovoltaic equipment faults.
Let $f^{(r)}(n;s,k)$ denote the maximum number of edges in an $n$-vertex $r$-uniform hypergraph containing no subgraph with $k$ edges and at most $s$ vertices. Brown, Erd\H{o}s and S\'os [New directions in the theory of graphs (Proc. Third Ann Arbor Conf., Univ. Michigan 1971), pp. 53--63, Academic Press 1973] conjectured that the limit $\lim_{n\rightarrow \infty}n^{-2}f^{(3)}(n;k+2,k)$ exists for all $k$. The value of the limit was previously determined for $k=2$ in the original paper of Brown, Erd\H{o}s and S\'os, for $k=3$ by Glock [Bull. Lond. Math. Soc. 51 (2019) 230--236] and for $k=4$ by Glock, Joos, Kim, K\"uhn, Lichev and Pikhurko [arXiv:2209.14177, accepted by Proc. Amer. Math. Soc.] while Delcourt and Postle [arXiv:2210.01105, accepted by Proc. Amer. Math. Soc.] proved the conjecture (without determining the limiting value). In this paper, we determine the value of the limit in the Brown-Erd\H{o}s-S\'os Problem for $k\in \{5,6,7\}$. More generally, we obtain the value of $\lim_{n\rightarrow \infty}n^{-2}f^{(r)}(n;rk-2k+2,k)$ for all $r\geq 3$ and $k\in \{5,6,7\}$. In addition, by combining these new values with recent results of Bennett, Cushman and Dudek [arXiv:2309.00182] we obtain new asymptotic values for several generalised Ramsey numbers.
Abstract At present, the energy efficiency optimization of an integrated energy system generally needs to optimize the allocation of each unit and structural resources of the system according to the real-time load data of the system to optimize the operation. However, the existing technology for system load forecasting is not accurate enough, resulting in the energy efficiency coefficient is still relatively low after system optimization. On this basis, this paper proposes an integrated energy system energy efficiency optimization technology based on digital twin technology. According to the actual situation of the system, the mathematical model is established. The equivalent analysis of the system is carried out, the digital twin technology is used to forecast the system load in real time, and constraint conditions and the objective function are constructed The optimal energy efficiency optimization strategy is obtained by rolling optimization. The experiment proves that the system energy efficiency coefficient is higher after the application of the design technology.
Food-grade high internal phase Pickering emulsions (HIPPEs) are stabilized by protein-based particles, which have attracted extensive attention due to their good gel-like structure. The black soybean isolate protein/cyanidin-3-O-glucoside (BSPI-C3G) covalent particles were used as a particulate emulsifier to form stable HIPPEs with oil phase fractions (74 % v/v) and low particle concentrations (0.5 %–3 % w/v) The particle size distribution and microstructure demonstrated that the BSPI-C3G covalent particles acted as an interfacial layer and surrounded the oil droplets. As the concentration of BSPI-C3G particles increased from 0.5 % to 3 %, the droplet size, elasticity, antioxidant capacity of the heated or stored HIPPEs more stable. So, the HIPPEs had the best stability with the BSPI-C3G particle at 3 % (w/v) concentration. These findings may extend the application of BSPI and C3G in foods and provide the guidelines for the rational design of food-grade HIPPEs stabilized by protein/anthocyanin complexes.
For seamless switching between two operating modes of a single microgrid vehicle and power sharing in islanding mode of multiple microgrid vehicles. We first establish the mathematical model of virtual synchronous generator system, and apply the secondary frequency regulation strategy to pre-synchronization on the basis of achieving priority protection for important loads, and change the virtual inertia, damping coefficient and pre-synchronization link of virtual synchronous generator by adjusting the virtual impedance to achieve seamless switching between grid-connected and off-grid modes. On this basis, an adaptive virtual impedance strategy is proposed to realize the balanced power distribution of multi-vehicle parallel system in islanding mode. Ensuring power supply quality and uninterrupted power supply for important loads and non-stop operation of distribution network. Build a microgrid model in Matlab/simlink to verify the effectiveness of the control scheme.
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